/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.test.web.servlet.request;

import java.net.URI;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import javax.servlet.ServletContext;
import javax.servlet.http.Part;

import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;
import org.springframework.lang.Nullable;
import org.springframework.mock.web.MockHttpServletRequest;
import org.springframework.mock.web.MockMultipartFile;
import org.springframework.mock.web.MockMultipartHttpServletRequest;
import org.springframework.util.Assert;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.multipart.support.StandardMultipartHttpServletRequest;

/**
 * Default builder for {@link MockMultipartHttpServletRequest}.
 *
 * @author Rossen Stoyanchev
 * @author Arjen Poutsma
 * @since 3.2
 */
public class MockMultipartHttpServletRequestBuilder extends MockHttpServletRequestBuilder {

    private final List<MockMultipartFile> files = new ArrayList<>();

    private final MultiValueMap<String, Part> parts = new LinkedMultiValueMap<>();


    /**
     * Package-private constructor. Use static factory methods in
     * {@link MockMvcRequestBuilders}.
     * <p>For other ways to initialize a {@code MockMultipartHttpServletRequest},
     * see {@link #with(RequestPostProcessor)} and the
     * {@link RequestPostProcessor} extension point.
     *
     * @param urlTemplate  a URL template; the resulting URL will be encoded
     * @param uriVariables zero or more URI variables
     */
    MockMultipartHttpServletRequestBuilder(String urlTemplate, Object... uriVariables) {
        super(HttpMethod.POST, urlTemplate, uriVariables);
        super.contentType(MediaType.MULTIPART_FORM_DATA);
    }

    /**
     * Package-private constructor. Use static factory methods in
     * {@link MockMvcRequestBuilders}.
     * <p>For other ways to initialize a {@code MockMultipartHttpServletRequest},
     * see {@link #with(RequestPostProcessor)} and the
     * {@link RequestPostProcessor} extension point.
     *
     * @param uri the URL
     * @since 4.0.3
     */
    MockMultipartHttpServletRequestBuilder(URI uri) {
        super(HttpMethod.POST, uri);
        super.contentType(MediaType.MULTIPART_FORM_DATA);
    }


    /**
     * Create a new MockMultipartFile with the given content.
     *
     * @param name    the name of the file
     * @param content the content of the file
     */
    public MockMultipartHttpServletRequestBuilder file(String name, byte[] content) {
        this.files.add(new MockMultipartFile(name, content));
        return this;
    }

    /**
     * Add the given MockMultipartFile.
     *
     * @param file the multipart file
     */
    public MockMultipartHttpServletRequestBuilder file(MockMultipartFile file) {
        this.files.add(file);
        return this;
    }

    /**
     * Add {@link Part} components to the request.
     *
     * @param parts one or more parts to add
     * @since 5.0
     */
    public MockMultipartHttpServletRequestBuilder part(Part... parts) {
        Assert.notEmpty(parts, "'parts' must not be empty");
        for (Part part : parts) {
            this.parts.add(part.getName(), part);
        }
        return this;
    }

    @Override
    public Object merge(@Nullable Object parent) {
        if (parent == null) {
            return this;
        }
        if (parent instanceof MockHttpServletRequestBuilder) {
            super.merge(parent);
            if (parent instanceof MockMultipartHttpServletRequestBuilder) {
                MockMultipartHttpServletRequestBuilder parentBuilder = (MockMultipartHttpServletRequestBuilder) parent;
                this.files.addAll(parentBuilder.files);
                parentBuilder.parts.keySet().stream().forEach(name ->
                        this.parts.putIfAbsent(name, parentBuilder.parts.get(name)));
            }

        } else {
            throw new IllegalArgumentException("Cannot merge with [" + parent.getClass().getName() + "]");
        }
        return this;
    }

    /**
     * Create a new {@link MockMultipartHttpServletRequest} based on the
     * supplied {@code ServletContext} and the {@code MockMultipartFiles}
     * added to this builder.
     */
    @Override
    protected final MockHttpServletRequest createServletRequest(ServletContext servletContext) {

        MockMultipartHttpServletRequest request = new MockMultipartHttpServletRequest(servletContext);
        this.files.stream().forEach(request::addFile);
        this.parts.values().stream().flatMap(Collection::stream).forEach(request::addPart);

        if (!this.parts.isEmpty()) {
            new StandardMultipartHttpServletRequest(request)
                    .getMultiFileMap().values().stream().flatMap(Collection::stream)
                    .forEach(request::addFile);
        }

        return request;
    }

}
